Heat exchanger of a vehicle provided with a protection grid

ABSTRACT

A heat exchanger of a vehicle, comprising a frame, a plurality of parallel tubes extending between two opposite sides of the frame, a pair of headers, each of which is arranged at a corresponding one of the two opposite sides of the frame, and a protection grid, attached at a face of the heat exchanger and including a plurality of parallel grid elements, in which each of the grid elements is adapted to shield a corresponding tube of the heat exchanger. 
     Fastening and supporting means are provided, by means of which opposite side edges of the protection grid are directly connected and firmly fastened to the frame or to the headers, and by means of which the protection grid is supported by the heat exchanger, and anchoring means, by means of which a lower edge of the protection grid is unfirmly retained to a lower side of the heat exchanger.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of Italian patent application numberTO2011A000187, filed Mar. 2, 2011, which is herein incorporated byreference.

DESCRIPTION

The present invention relates to a heat exchanger of a vehicle,comprising

-   -   a frame,    -   a plurality of parallel tubes extending between two opposite        sides of the frame,    -   a pair of headers, each of which is arranged at a corresponding        one of said two opposite sides of the frame, and    -   a protection grid, attached at a face of the heat exchanger and        including a plurality of parallel grid elements, wherein each of        said grid elements is adapted to shield a corresponding tube of        the heat exchanger.

Protection grids are conventionally used in motor vehicles to protectheat exchangers such as heaters and condensers.

In fact, it is known that, during its life, a heat exchanger forautomotive applications is subject to damages caused by the impact fromstones during the ride of the vehicle. One of the solutions to eliminateor at least mitigate the risk of damage provides precisely for theapplication of a protection grid on the front face of the heatexchanger.

A solution of this kind is described, for example, in the publication EP0 980 504, which has a heater in which the protection grid is attachedto the heater tubes by clips.

Such solution has several drawbacks. First, since there are differentheaters with different geometries of the tubes, it is necessary toarrange different clips that are adapted to such different geometries.Secondly, since the clips have to operate in an elastic field, inheaters having significant thicknesses the clips can be structurallyweak and not very efficient during operation. Furthermore, in the caseof manual assembly, the proper application of the clips can be checkedonly by visual control. Another drawback is related to the fact that theapplication of components to the tubes may adversely affect theintegrity of the latter, in both the production process, and duringoperation. Moreover, since the clips are in contact with the heatertubes, the heat emitted by the latter can cause a dilatation of theclips, with consequent weakening of the mechanical seal. Furthermore, itis difficult to manufacture a joint that is free from vibrations.

Therefore, an object of the present invention is to provide a heatexchanger with a protection grid that is able to at least partiallyobviate the above stated drawbacks.

Such object is achieved according to the invention by a heat exchangerof the type defined in the beginning, in which fastening and supportingmeans are provided, by means of which opposite side edges of theprotection grid are directly connected and firmly fastened to the frameor to the headers, and by means of which the protection grid issupported by the heat exchanger, and anchoring means by means of which alower edge of the grid is unfirmly retained to a lower side of the heatexchanger.

Such solution allows achieving an almost all-purpose assembling system,since the fastening and supporting means and the anchoring means are notaffected by the geometry of the tubes, therefore they can be used indifferent models of exchanger. Moreover, the higher degree ofstandardization of the solution allows objectively checking thesuitability of the assembly. Furthermore, inasmuch it is given up toattach components to the tubes of the exchanger, on one hand, the riskof causing damages to such tubes is avoided, and, on the other hand, anypossible adverse impact of the thermal effects on the quality of themechanical seal of the assembly is prevented.

Preferred embodiments of the invention are defined in the dependantclaims, which are meant as an integral part of the presentspecification.

Further characteristics and advantages of the exchanger according to theinvention will be more clearly understood from the following detaileddescription of some embodiments of the invention, given with referenceto the annexed drawings, which are provided by way of example only, andnot as a limitation, in which:

FIG. 1 is an axonometric view of the lower part of a heat exchangeraccording to the invention;

FIGS. 2 and 3 are views at an enlarged scale of details indicated by thearrow II and the arrow III of FIG. 1, respectively;

FIG. 4 is a view at an enlarged scale and from below of a detail,according to the arrow IV of FIG. 1;

FIGS. 5 and 6 are front and rear views, respectively, of a protectiongrid of the heat exchanger of FIG. 1;

FIGS. 7 and 8 are views that show a second embodiment of a heatexchanger according to the invention, with and without the protectiongrid, respectively;

FIG. 9 is a side view at an enlarged scale of a detail, according to thearrow IX of FIG. 7;

FIGS. 10 and 11 are views at an enlarged scale of details indicated bythe arrow X and the arrow XI of FIG. 7, respectively;

FIG. 12 is a simplified cross-sectional view of a lower portion of theexchanger of FIG. 7.

In the following description, and in the claims, spatial terms such as“upper”, “lower”, “side”, “front”, and “rear” and other ones arereferred to the usual installation arrangement of the heat exchangeronto vehicles.

The heat exchanger can be, for example, a heater, a condenser, anintercooler, or an oil cooler.

With reference to the FIGS. 1 to 6, a heat exchanger according to theinvention is generally indicated by 1.

The exchanger 1 conventionally comprises a frame 3, which includes rightand left side plates 3 a, 3 b, an upper plate, which is not visible inthe Figures, and a lower plate, visible in FIG. 4 and indicated by 3 d.The above-mentioned plates are mutually interconnected in a conventionalmanner so as to form the frame 3.

The exchanger 1 further comprises a plurality of parallel tubes 5extending between opposite sides of the frame 3. In the exampleconsidered, the exchanger is of the type having horizontal tubes,therefore the tubes 5 extend between the right and left side plates 3 a,3 b of the frame 3. Tongues—not shown—can be arranged in the interspacesbetween the tubes 5.

The exchanger 1 further comprises a pair of headers 7 a, 7 b, each ofwhich is arranged at a corresponding one of said two opposite sides ofthe frame 3. In the example considered, the headers 7 a, 7 b arearranged at the right and left side plates 3 a, 3 b of the frame 3. Suchheaders 7 a, 7 b are generally, but not exclusively, of a plasticmaterial.

The exchanger 1 further comprises a protection grid 10, attached at aface (in particular, the front face) of the heat exchanger 1 andincluding a plurality of parallel grid elements 11, in which each ofsuch grid elements 11 is adapted to shield a corresponding tube 5 of theheat exchanger 1. The protection grid 10 is in particular an elementmade integrally of plastic or metal material, and the grid elements 11are constituted by little bars that are spaced apart one from another,having a pitch corresponding to the pitch of the tubes of the exchanger.The little bars can be mutually connected by reinforcing bridges.

The protection grid 10 comprises right and left side edges 13 a, 13 b,an upper edge 13 c, and a lower edge 13 d, defining the extension areaof the grid elements 11. The protection grid 10 can extend so as tocover the whole exchanger, or only the lower portion thereof, as in theillustrated example.

In the exchanger illustrated, fastening and supporting means 15 areprovided, by means of which the side edges 13 a, 13 b of the protectiongrid 10 are directly connected and firmly fastened to the headers 7 a, 7b, and by means of which the protection grid 10 is supported by the heatexchanger 1, and anchoring means 17 by means of which the lower edge 13d of the protection grid 10 is unfirmly retained to a lower side of theheat exchanger 1.

To the aims of the present invention, it is meant that two elements aremutually “directly” connected if there is no intermediate elementconnecting them, except for the fastening and supporting means.Furthermore, it is meant that two elements are mutually “firmly”attached if they can be divided one from the other by disabling orremoving the fastening and supporting means, which therefore make aremovable connection.

Finally, it is stated that the lower edge of the protection grid is“unfirmly” retained to the lower side of the heat exchanger, by theanchoring means, in the sense that the retention operated by theanchoring means is lost when the fastening and supporting means aredisabled or removed, which make the firm fastening of the grid to theexchanger. In particular, the “unfirm” retention is achieved due to thefact that the lower edge of the protection grid engages by interferencethe lower side of the heat exchanger.

In the illustrated example, the fastening and supporting means areconstituted, for each side edge of the protection grid 10, by a pair ofsnap-fit spring tongues 15 a, 15 b and by a dowelling and supportingformation 16 a, 16 b, wherein the spring tongues 15 a, 15 b and the andsupporting formations 16 a, 16 b are integrally formed on the body ofthe corresponding header 7 a, 7 b.

Each spring tongue 15 a, 15 b extends in a direction perpendicular tothe plane of the exchanger, and is arranged in such a way as to beadapted to bend in a vertical direction, being provided with arespective detent 15 c, 15 d adapted to engage a corresponding portionof the protection grid 10. To this aim, each side edge 13 a, 13 b of theprotection grid is provided with a corresponding ear portion 14 a, 14 blaterally extending so as to overlap the corresponding header 7 a, 7 b,and has an aperture 14 c, 14 d adapted to be snap-fit by thecorresponding pair of snap-fit spring tongues 15 a, 15 b. As it can benoted in the Figures, one of the apertures 14 c, 14 d (in the example,the one on the right, 14 c) has a greater width in the horizontaldirection, in order to compensate possible manufacturing tolerances.

Each dowelling and supporting formation 16 a, 16 b extends in adirection perpendicular to the plane of the exchanger and is T-shaped incross-section. Each dowelling and supporting formation 16 a, 16 b is forfitting into a T-shaped aperture 14 e, 14 f formed in the correspondingear portion 14 a, 14 b. As it can be noted in the Figures, one of theshaped apertures 14 e, 14 f (in the example, the one on the right, 14 e)has a greater width in the horizontal direction, in order to compensatepossible manufacturing tolerances. While the snap-fit spring tongues 15a, 15 b mainly (or exclusively) exert a retaining function of theprotection grid 10 in a direction perpendicular to the plane of theexchanger, dowelling in the directions parallel to the plane of theexchanger and supporting of the protection grid 10 are performed mainly(or exclusively) by the dowelling and supporting formations 16 a, 16 b.

In an alternative embodiment, not shown, the fastening and supportingmeans are constituted by screws or rivets fitted into correspondingbores formed on the side edges 13 a, 13 b, and engaging correspondingseats formed on the body of the headers 7 a, 7 b in such a way to firmlyfasten the protection grid thereto. In such a case, the fastening,dowelling, and supporting functions are performed by the same elements.

With reference in particular to the FIGS. 4 and 6, the above-mentionedanchoring means 17 are constituted by at least one hook portion 17 aintegrally formed on and extending rearward from the lower edge 13 d ofthe protection grid 10. Said at least one hook portion 17 a is adaptedto engage a corresponding portion of the lower plate 3 d of the frame 3of the exchanger, so as to unfirmly retaining the lower edge 13 d of theprotection grid 10 to the lower side of the heat exchanger 1. Suchexpedient allows reducing or eliminating possible vibrations associatedto the lower central part of the protection grid 10, while not requiringcomplex coupling operations upon assembling the grid on the exchanger.

Preferably, in order to reduce or eliminate possible vibrationsassociated to the upper central part of the protection grid, an engagingformation (not shown) adapted to snap-fit one (or two) of the tubes 5 ofthe heat exchanger is integrally formed on the upper edge 13 c of theprotection grid 10.

Still more preferably, at least one preload curvature is formed on theprotection grid 10, which, in the assembled condition, elasticallybiases the grid elements 11 against the tubes 5 of the exchanger tofurther reduce the onset of vibrations. Alternatively, or in addition,one or more preload ribs can be further present.

Alternatively, or in addition, a vibration-damping element (not shown)is sandwiched between the protection grid 10 and the tubes 5 of theexchanger, in a shock-absorbing material, such as, for example, rubber,which is arranged in such a way as to be pressed between the protectiongrid 10 and the tubes 5. Such vibration-damping element can bemechanically attached on the protection grid 10, or moulded thereon.

With reference to the FIGS. 7 to 11, a second embodiment of a heatexchanger according to the invention, generally indicated by 1, isillustrated. Elements corresponding to those of the preceding embodimenthave been indicated by the same reference numbers and, for what has notbeen explicitly described herein, reference is made to the precedingportion of the description. The second embodiment of the FIGS. 7 to 11differs from the preceding one mainly in that the exchanger ismanufactured according to a vertical tubes scheme.

In the example considered, therefore, the tubes 5 extend between theupper 3 c and lower 3 d plates of the frame 3, and the headers 7 a, 7 bare arranged at such plates.

In the exchanger illustrated, fastening and supporting means 15 areprovided, by means of which the side edges 13 a, 13 b of the protectiongrid 10 are directly connected and firmly fastened to the side plates 3a, 3 b, and by means of which the protection grid 10 is supported by theheat exchanger 1, and anchoring means 17 by means of which the loweredge 13 d of the protection grid 10 is unfirmly retained to a lower sideof the heat exchanger 1.

In the example illustrated, the fastening and supporting means areconstituted, for each side edge of the protection grid 10, by a pair ofsnap-fit spring tongues 15 a, 15 b and by a dowelling and supportingformation 16 a, 16 b, wherein the spring tongues 15 a, 15 b and thedowelling and supporting formations 16 a, 16 b are formed integrally ona support element 21 a, 21 b that is attached, for example by rivets, tothe corresponding side plate 3 a, 3 b.

In turn, each side edge 13 a, 13 b of the protection grid is providedwith a corresponding coupling portion 23 a, 23 b that is arranged so asto overlap the corresponding support element 21 a, 21 b, and having anaperture 14 c, 14 d adapted to be snap-fit by the corresponding pair ofsnap-fit spring tongues 15 a, 15 b.

Each dowelling and supporting formation 16 a, 16 b is for fitting into aT-shaped aperture 14 e, 14 f formed in the corresponding couplingportion 14 a, 14 b.

With reference in particular to the FIG. 12, the above-mentionedanchoring means 17 are constituted by at least one tab portion 17 aintegrally formed on and extending downward from the lower edge 13 d ofthe protection grid 10. Said at least one tab portion 17 a is adapted toengage a corresponding slot of the lower plate 3 d of the frame 3 of theexchanger, so as to unfirmly retain the lower edge 13 d of theprotection grid 10 to the lower side of the heat exchanger 1. Suchexpedient allows reducing or eliminating possible vibrations associatedto the lower central part of the protection grid 10, while not requiringcomplex coupling operations upon assembling the grid on the exchanger.

As it can be noticed in the FIGS. 7 and 9, a vibration-damping element25, of shock-absorbing material is sandwiched between the protectiongrid 10 and the tubes 5 of the exchanger, such as, for example rubber,which is arranged in such a way as to be pressed between the protectiongrid 10 and the tubes 5. Such vibration-damping element can bemechanically attached on the protection grid 10, or moulded thereon. Inthe example illustrated, the vibration-damping element 25 ismechanically attached to a corresponding portion of the protection grid10, by means of barbs integrally formed on the vibration-damping element25 and inserted into corresponding bores formed on the protection grid.

1. A heat exchanger of a vehicle, comprising a frame, a plurality ofparallel tubes extending between two opposite sides of the frame, a pairof headers, each of which is arranged at a corresponding one of said twoopposite sides of the frame, and a protection grid attached at a face ofthe heat exchanger and including a plurality of parallel grid elements,wherein each of said grid elements is adapted to shield a correspondingtube of the heat exchanger, characterized in that fastening andsupporting means are provided, by means of which opposite side edges ofthe protection grid are directly connected and firmly fastened to theframe or to the headers, and by means of which the protection grid issupported by the heat exchanger, and anchoring means are provided, bymeans of which a lower edge of the protection grid is unfirmly retainedto a lower side of the heat exchanger.
 2. An exchanger according toclaim 1, wherein the fastening and supporting means are constituted, foreach side edge of the protection grid, by a pair of snap-fit springtongues for snap-fitting into a corresponding aperture arranged at theside edge of the protection grid, and by a dowelling and supportingformation for fitting into a corresponding shaped opening arranged atthe side edge of the protection grid, wherein support of the protectiongrid on the heat exchanger is mainly provided by the dowelling andsupporting formation.
 3. An exchanger according to claim 2, wherein eachspring tongue extends in a direction perpendicular to the plane of theheat exchanger and is arranged in such a way as to be adapted to bend ina vertical direction, being provided with a respective detent adapted toengage a corresponding portion of the protection grid.
 4. An exchangeraccording to claim 2, wherein each dowelling and supporting formationextends in a direction perpendicular to the plane of the exchanger andis T-shaped in cross-section, the corresponding shaped opening beingcorrespondingly T-shaped.
 5. An exchanger according to claim 2, whereinthe aperture and the shaped opening associated to one of the side edgesof the protection grid are wider in the horizontal direction than theaperture and the shaped opening associated to the other of the sideedges of the protection grid.
 6. An exchanger according to claim 2,wherein the spring tongues and the dowelling and supporting formationsare integrally formed on the body of said headers, or on supportelements respectively attached to side plates of the frame.
 7. Anexchanger according to claim 2, wherein said apertures and shapedopenings are arranged on respective ear portions laterally extendingfrom each side edge of the protection grid.
 8. An exchanger according toclaim 1, wherein said fastening and supporting means are constituted byscrews or rivets fitted into corresponding bores formed on the sideedges of the protection grid, and engaging corresponding seats arrangedon the frame or on the headers in such a way to firmly fasten theprotection grid thereto.
 9. An exchanger according to claim 1, whereinsaid anchoring means are constituted by at least one hook portionintegrally formed on and extending rearward from the lower edge of theprotection grid, said at least one hook portion being adapted to engagea corresponding portion of a lower plate of the frame of the heatexchanger.
 10. An exchanger according to claim 1, wherein said anchoringmeans are constituted by at least one tab portion integrally formed onand extending downward from the lower edge of the protection grid, saidat least one tab portion being adapted to engage a corresponding slot ofa lower plate of the frame of the heat exchanger.
 11. An exchangeraccording to claim 1, wherein at least one preload curvature is formedon the protection grid for elastically biasing at least one of the gridelements against at least one of the tubes of the heat exchanger.
 12. Anexchanger according to claim 1, wherein the protection grid is providedwith a vibration-damping element of shock-absorbing material, which isarranged in such a way as to be pressed between the protection grid andthe tubes of the heat exchanger.